If Gregorius were to be placed on the disabled list, Ronald Torreyes and lefty-hitting Tyler Wade – both on the 40-man roster – would be replacement candidates.

Top-ranked Yankees infield prospect Gleyber Torres has had an outstanding spring, but the 20-year-old has not played a game above Class A and is not likely to be considered. But fellow non-roster shortstops Ruben Tejada, Pete Kozma and Donovan Solano are candidates to make the club.

And Castro said he would be willing to switch back to shortstop if needed.

“If it’s going to be a DL (situation), we’ve got a lot more to discuss than maybe we thought we had to discuss,’’ Girardi said of the Yankees’ unresolved right field, bullpen and final two rotation spots.

Speaking with reporters at West Palm Beach, where the Yankees were wrapping up a two-game Grapefruit League swing, Girardi said that Gregorius “complained of some stiffness in his arm’’ in Arizona, where Team Netherlands played a “warm-up’’ game Saturday against the Diamondbacks.

After an initial exam of Gregorius’ shoulder, “the doctor was really encouraged by his strength and felt good about it, but we thought (we should) cover ourselves,’’ Girardi said of sending Gregorius for further tests. “Because we haven’t seen him, we don’t know exactly what it means.’’

Gregorius was having a fine WBC tourney, slashing .348/.385/.652 in six WBC games, with four doubles, a home run and eight RBI – helping the Netherlands into Monday night’s semifinal against Puerto Rico.

“It has to be extremely disappointing for him,’’ said Girardi, who spoke with Gregorius briefly on Sunday. “It had to be really exciting and he was doing great (in the WBC). It’s got to be tough.’’

And it’s not easy on clubs who have valuable players at the WBC, with executives merely hoping that their players return healthy from a preseason exhibition series – one played with a lot of nationalistic fervor.

“The intensity level goes up quicker than what they’re used to and that’s always a concern of ours,’’ Girardi said.

Before the 2013 WBC began, the Yankees lost Mark Teixeira to a right wrist injury that later required surgery – effectively ruining two seasons.

Teixeira was taking swings with a weighted bat so it’s difficult to gauge whether some injuries to players might have eventually surfaced in their own camps.

“They’re not with you. They’re not in your hands and that’s the hard part,’’ Girardi said. “I mean, arm injuries, as we see, can happen. The thing is, he hasn’t played a ton of defense.’’

In his second year in pinstripes, Gregorius had a breakthrough 2016, batting .276 with 20 homers and 70 RBI and displaying Gold Glove-caliber defense.

“The strides he took last year (and) what he did, that’s a big loss,’’ Girardi said if Gregorius were to be sidelined for any length of time.